As shown in FIGS. 1-3, a prior art screwdriver comprises a shank 10, a handle 11 fastened with one end of the shank 10, and a tip 16 fastened with other end of the shank 10. The shank 10 has a hollow interior 12 in which an expandable rod 14 is disposed. The shank 10 has an open end 13 through which the expandable rod 14 is extracted or retracted. The expandable rod 14 is provided at the outer end thereof with a magnetic element 15 fastened therewith for attracting a screw which is located at a hard-to-reach place.
Such a prior art screwdriver as described above is defective in design in that the expandable rod 14 and the tip 16 interfere with each other when the screwdriver is in use or when the tip 16 of one size is replaced with the tip 16 of another size.